The Prime Power Unit (PPU) is an air- and highway-transportable, trailer-mounted 1.3MW (megawatt) Generator Set, a key component of the Terminal High Altitude Air Defense (THAAD) system.

The trailer-sized Green Energy Machine (GEM) is the first all-in-one, on-site device to produce clean energy from trash, letting business parks, universities and towns make their own power.

Described are the composition, features and preventative measures for the power supply system on the trailer car of the 270 km/h EMU.